Submarines: How They Work  Archimedes' Principle
Archimedes' principle is the law
of buoyancy. It states that "any body partially or completely submerged
in a fluid is buoyed up by a force equal to the weight of the fluid
displaced by the body." The weight of an object acts downward, and
the buoyant force provided by the displaced fluid acts upward. If
these two forces are equal, the object floats. Density is defined
as weight per volume. If the density of an object exceeds the density
of water, the object will sink.
